Fix for issue 14790 - Crash when using dartium devtools

runtime/vm/instructions_x64_test.cc

Index: runtime/vm/instructions_x64_test.cc
===================================================================
--- runtime/vm/instructions_x64_test.cc	(revision 29988)
+++ runtime/vm/instructions_x64_test.cc	(working copy)
@@ -28,10 +28,11 @@
 
 
 ASSEMBLER_TEST_GENERATE(Jump, assembler) {
-  __ EnterDartFrame(0);  // 20 bytes
+  __ pushq(PP);  // Save caller's pool pointer and load a new one here.
+  __ LoadPoolPointer(PP);
   __ JmpPatchable(&StubCode::InstanceFunctionLookupLabel(), PP);
   __ JmpPatchable(&StubCode::AllocateArrayLabel(), PP);
-  __ LeaveFrameWithPP();
+  __ popq(PP);  // Restore caller's pool pointer.
   __ ret();
 }